docs(readme): fix Library use example — package name and renderTextToImages

The 'Library use' snippet imported `renderTextToPngs` from "pxpipe", but the
published package is "pxpipe-proxy" and the root barrel (src/core/index.ts)
exports `renderTextToImages`, not `renderTextToPngs`. Both the import
specifier and the function name were unrunnable as written.

- import from "pxpipe-proxy" (matches package.json "name")
- use renderTextToImages, which returns { pages, droppedChars, pixels }
- show pages[i].png (Uint8Array) instead of the stale RenderedImage[] comment

README.md

@@ -117,9 +117,9 @@ sparse prose stays text. Events log to `~/.pxpipe/events.jsonl`.
 ## Library use (no proxy)
 
 ```ts
-import { renderTextToPngs, transformAnthropicMessages } from "pxpipe";
+import { renderTextToImages, transformAnthropicMessages } from "pxpipe-proxy";
 
-const imgs = await renderTextToPngs(toolResultText);            // RenderedImage[]
+const { pages } = await renderTextToImages(toolResultText);     // pages[i].png: Uint8Array
 const { body, applied, info } = await transformAnthropicMessages({
   body: requestBytes,
   model: "claude-fable-5",